struct TreeNode* searchBST(struct TreeNode* root, int val)
{
    if (!root || root -> val == val) 
    {
        return root;
    } 
    else if (root -> val > val) 
    {
        root = root -> left;
        root = searchBST(root, val);
    } 
    else 
    {
        root = root -> right;
        root = searchBST(root, val);
    }
    return root;
}

